Revised November 2009

Attention deficit hyperactivity disorder (ADHD) is the most common psychiatric disorder in childhood. Several interventions are effective in treating children with ADHD, including medications and behavior therapy. To examine how intensive treatment with medications compares with intensive behavior therapy, or with the combination of the two, NIMH sponsored the Multimodal Treatment of ADHD (MTA) study. The main findings from this study were published in December 1999, and are discussed below.

Q. What is the MTA?

A. The MTA was a multisite study designed to evaluate the leading treatments for ADHD, including behavior therapy, medications, and the combination of the two. The study included nearly 600 children, ages 7-9, who were randomly assigned to one of four treatment modes:

intensive medication management alone;

intensive behavioral treatment alone;

a combination of both; or

routine community care (the control group).

Q. Why is the MTA important?

A. While previous studies have examined the safety and compared the effectiveness of medication and behavior therapy for ADHD, they generally were short-term—no more than four months. The MTA study examined for the first time the safety and relative effectiveness of these two treatments—alone and in combination for a time period of up to 14 months, and compared these treatments to routine community care.

Q. What are the major findings of the MTA?

A. The MTA primary results were published in December 1999 in the Archives of General Psychiatry. Combination treatment and medication management alone were both significantly superior to intensive behavioral treatment alone and to routine community care in reducing ADHD symptoms. The study also showed that these benefits last for as long as 14 months.

In other areas of functioning (e.g., anxiety symptoms, academic performance, parent-child relations, and social skills), combination treatment was consistently superior to routine community care, whereas medication alone or behavioral treatment alone were not. The children in the combination treatment also ended up taking lower doses of medication than the children in the medication-alone group. These findings were consistent across all six research sites, despite substantial differences among sites in the children's sociodemographic characteristics. Therefore, the study's overall results can apply to a wide range of children and families in need of treatment services for ADHD.

Q. What did the MTA tell us about the safety of stimulant medication?

A. Of the 289 children randomized to medication, 4 percent had adverse effects severe enough to prompt them to discontinue the medication. Adverse effects included loss of appetite, sleep problems, crying spells, and repetitive movements. Medication also slowed the physical growth of children during the 14 months of treatment. The children who received intensive medication treatment (seven days a week) grew 4.25 cm on average and gained 1.64 kg on average, while the children who received behavior therapy only (no medication) grew 6.19 cm on average and gained 4.53 kg on average.1 Over time, these growth effects may persist if medication is continued.2 However, 88 percent of the children were successfully treated for the full duration of the study.

Q. What is the role of behavioral therapy in treating ADHD?

A. Research has shown that behavioral therapies are very effective in treating children with ADHD. However, the MTA study demonstrated that, on average, carefully monitored medication with monthly follow-up is more effective than intensive behavioral treatment alone, for up to 14 months.

All children improved over the course of the study, but they differed in the relative amount of improvement. The children receiving medication management, either alone or in combination with behavior therapy, generally showed the greatest improvement. However, children's responses varied enormously, and some children did very well in each of the treatment groups.

For some types of functioning, such as academic performance and family relations, the combination of behavioral therapy and medication was superior to the other treatment groups. Therefore, medication alone is not necessarily the best treatment for every child, and families often need to pursue other treatments, either alone or in combination with medication.

Q. Which treatment is right for my child?

A. Parents must consult with their child's doctor to determine the best course of treatment for their child. No single treatment is best for all children with ADHD. Families should consider side effects of medications, or other circumstances that might render certain treatments inappropriate for their child.

Children with coexisting conditions such as anxiety or external stressors such as high levels of family conflict may do best with a combination of treatments. When determining a suitable treatment, a child's needs, personal and medical history, and other relevant factors need to be carefully considered.

Q. Why do many social skills improve with medication?

A. Previously, it was thought that children with ADHD could only learn new social skills if they were explicitly taught. However, the MTA study findings suggest that many children can acquire these skills on their own when given the opportunity. Children treated with medication management (either alone or in combination with intensive behavioral therapy) showed more improved social skills and peer relations than children in the community comparison group after 14 months. This finding suggests that symptoms of ADHD may interfere with a child's ability to learn specific social skills. Medication may help them learn these skills by diminishing symptoms that had previously inhibited the child's social development.

Q. Why were the MTA medication treatments more effective than community treatments that also usually included medication?

A. There were substantial differences in quality and intensity between the study-provided medication treatments and those provided in the community care group. During the first month of treatment, the MTA doctors worked hard to find the best dose of medication for each child receiving the MTA medication treatment. After this period, the children saw their MTA doctor monthly.

During the treatment visits, the doctor spoke with the parent, met with the child, and worked to determine any concerns that the family might have regarding the medication or the child's ADHD. If the child was experiencing any difficulties, the MTA doctor could adjust the child's medication, In contrast, the community treatment doctors generally saw the children face-to-face only one or two times per year.

Careful monitoring also allowed for early detection and response to any side effects from the medication, which probably helped the children stay on the medication. In addition, the MTA doctors consulted with each child's teacher on a monthly basis, and used this information to make any necessary adjustments in the child's treatment. In contrast, the community treatment doctors did not interact regularly with the children's teachers.

Finally, the MTA doctors delivering the medication treatments generally prescribed higher doses of stimulant medications per day than the community treatment doctors.

Q. How were children selected for this study?

A. Parents heard about the study through their pediatricians and other health care providers, their children's teachers, or through radio/newspaper announcements. They then contacted the investigators. Study investigators interviewed the children and parents to learn more about the nature of the child's symptoms and medical history, and rule out other conditions or factors that may be causing the child's difficulties. The children needed to meet strict criteria to be eligible for the study.

Q. What are the main limitations of the MTA, and what happened after it concluded?

A. The MTA was designed and conducted in the early 1990s, before the extended release formulations of stimulant medications became widely available. The MTA used immediate release methylphenidate (Ritalin), which was administered three times a day. Currently, most children receiving stimulant treatment for ADHD are given a once-a-day dose of medication in the morning. However, this difference in medication administration does not change the study's main conclusions.

In addition, the MTA treatment lasted for 14 months only, after which the children were referred back to their community providers. Some of them continued treatment. Others discontinued their treatment or changed it, based on their individual situation. All participants, regardless of the treatment they received, were invited to return to the MTA clinics every one to two years for an assessment of their ADHD symptoms and level of functioning.

Because their treatment after the end of the study was not controlled, it is not possible to draw accurate conclusions about the effectiveness of interventions beyond 14 months, or determine if treatment improves long-term functioning. However, the observations collected from these uncontrolled follow-up assessments can provide information about the long-term course of ADHD itself. These data are being analyzed and reported as they become available.3

Q. Where did this study take place?

A. The study was conducted at the following clinical research sites:

New York State Psychiatric Institute at Columbia University, New York, NY.

Mount Sinai Medical Center, New York, NY

Duke University Medical Center, Durham, NC

University of Pittsburgh, Pittsburgh, PA

Long Island Jewish Medical Center, New Hyde Park, NY

Montreal Children's Hospital, Montreal, Canada

University of California at Berkeley, CA

University of California at Irvine, CA

Q. Where can I find more information about the MTA study?

A. In addition to the information available on the NIMH Web site on MTA the following is a selection of MTA references: